Improvement in dental-engine hand-pieces



E. T. STARR. DENTAL-ENGINE HAND-PIECES. 19;,85o.

.Patented Sept.4,11877.

By fuk ttornal/S,

N. PETERS. PHDTOLITHOGRAPHER, WAHINGON, Dv C.

UNITED STATES S. WHITE, OF SAME PLAGE.

IMPROVEMENT IN DENTAL-ENGINE HAND-PIECES.

Specification forming part of Letters Patent No. lili-L85@ datedSeptember 4, 1877; application filed March 22, 1877.

To all whom Iit may concern.-

Be it known that I, ELI T. STARR, of the city and county ofPhiladelphia, and State of Pennsylvania, have invented certain new anduseful Improvements in Dental-Engine Hand- Pieces, of which thefollowing is a specification:

My invention constitutes an improvement upon the hand-piece shown inLetters Patent of the United States granted to me November 16, 1875, asNo. 170,125, the shell or casing of which is composed of sectionsseparable from each other for .the ready inspection of the chuck ortool-holder mounted therein, and is so connected with the flexiblenon-rotating sheath of a dental engine,V through which passes a flexiblepower-driven shaft to impart motion to the tool-chuck, that the casingis free to swivel to conform to the movements of the hand of theoperator without liability of the sections becoming separated.

The object of my invention is to improve andrender more efficient thedevice for preventing accidental separation of the sections, whileallowing` them readily and quickly to be separated when it is desired toinspect theinterior of the hand-piece.

The subject-matter claimed hereinafter speciiically will be designated.

In the accompanyingdrawings, Figure l represents a longitudinal centralsection through the hand-piece and the end of the sheath to which it isattached on the line 1 l of Figs. 2 and 3; Fig. 2, a view, partly insection, of the spring-clutch to prevent accidental separation of thesections 5 Fig. 3, a view similar to Fig. 2, showing the exterior of theclutch; Fig. 4, a transverse section through the handpiece and clutch onthe line 2 2 of Figs. 1, 2, andfnl; and Fig. 5, a plan view of ahandpiece embodying my improvements. v

The hand-piece, shell, or casing is shown as composed of four sections,A A1 A2 A3, as usual, the inner one, A, being firmly secured to aiiexible non-rotating sheath, B, which may be similar to that employedin the wellknown S. S. White dental engine, through which a exiblepower-driven shaft, C, passes to impart motion to a chuck ortool-holder, D, of any improved construction, mounted in the casing. l

The second section, A1, is connected to the tiXed section by aswivel-joint, a, of wellknown construction, so as to permit it and thebalance of the casing to turn freely to conform to the movements of thehand of the operator.

The third section, A2, which envelops the chuck or tool-holder, isconnected to the swiveling section by screw-threads, as usual, so as topermit of its ready detachment for inspecting the chuck, and carriesupon its end the fourth section, A3, or nose of the handpiece.

These parts are substantially like those shown in my former patent.

To prevent accidental separation ofthe detachable and swiveling sectionswhen turning to conform to the movements of the hand of the operator, Imount upon the swiveling section a spring-clutch, consisting, in thisinstance, of a sleeve or barrel, E, provided with a pin or lug, e,working in a groove, e', in said section, the pin being adapted to entera notch cut in the end of the detachable section, when it is screwedupon the swiveling section to lock the two together, the tension of aspiral spring, E', inclosed within the sleeve or barrel, beingconstantly exerted to throw forward the clutch, which must be retractedbefore the sections can be unscrewed or separated.

This spring-clutch is intended to obviate some defects incident to theclutch shown in my patent aforesaid, and has in practice been found veryefficient, permitting of the ready and quick separation of the sectionswhen desired, and also of a handsome and smooth tinish being given tothe exterior of the handpiece throughout.

I claim as of my own inventionl. A swiveling sectional hand-pieceprovided with a spring-clutch between the detachable sections to preventaccidental separation thereof when turning to conform to the inciosedWithin the sleeve, whereby accidentali movements of the hand of theoperator, subdisconnection of the sections is prevented. stantially asdescribed. In testimony whereof I have hereunto sub- 2.. Thecombination, substantially as herescribed my name.

inbefore set forth of the swiveling and detachable sections ,of thehand-piece with the ELI T' STARR overlapping sliding sleeve carryingapin Work- Witnesses ing in a groove in one section and interlock- J. A.B. WILLIAMS,

ing with a notch in the other, and the spring JULES M. BAND.

